Element 1 - Testing & Analysis
Task No. 1.3.3 Dynamic Characteristics of Woodframe Buildings
PI: James Beck (California Institute of Technology)
Much research has been done on the dynamic and cyclic characteristics of wood subsystems and connection panels, but full-scale testing of wood shear-wall buildings has been sparse. This scarcity emphasizes the importance of Task 1.3.3 because the dynamic characteristics of woodframe buildings as a whole must be better understood in order to improve current building practices and to establish code requirements for the safe and cost-effective design of these buildings.
To determine the dynamic characteristics (natural frequencies and damping) of woodframe structures and to develop a period formula specific for wood structures by regressing on appropriate structural characteristics. We focused on the fundamental mode behavior, which tends to dominate the dynamic characteristics. We also focused on low-rise shear-wall buildings, as this is the predominant type of wood-frame construction in North America.
Through analysis of recorded earthquake response and by forced and ambient vibration testing, Task 1.3.3 has developed a database of periods, damping ratios and mode shapes of woodframe buildings; in particular, this database has enabled us to develop a more accurate period formula for design purposes. Upon completion of the testing phase, a regression analysis was performed, using building height as the structural parameter expected to control the building periods. The goal was to produce a simple but reasonably accurate formula for predicting a building’s fundamental period.
• Table summarizing the building parameters and the dynamic characteristics obtained from system identification analysis of these earthquake records
• CUREE Report : W-11: Dynamic Characteristics of Woodframe Structures